The broad objectives of this proposal are to identify converging clinical, neuroanatomical, and electrophysiological features and clinicopathological relationships in idiopathic schizophrenia (ISZ) as compared to epilepsy patients with interictal schizophrenia-like syndromes (ESZ) and localization-related epilepsy of unilateral temporal lobe or frontal lobe origin without interictal psychosis. Healthy controls provide normative EEG, MRI, and neuropsychological data. Such knowledge will help establish the location, specificity, and pathophysiological significance of abnormalities in ISZ and further direct studies of regional neuropathology and brain dysfunction in ISZ to focus on areas of etiologic significance. Findings to date show that the ESZ subjects resemble the ISZ subjects clinically, with prominent psychotic as well as negative symptoms, as well as similar evidence for prefrontal cognitive dysfunction. As such, ESZ represents a clinical phenotype of idiopathic schizophrenia. The neuroanatomical data to date show evidence for temporal lobe and extratemporal lobe cortical gray matter deficits in the ISZ, ESZ, and nonpsychotic TLE subjects. However, the deficits are significantly greater in the ESZ. This suggests commonalties in the underlying pathology of epilepsy and schizophrenia, with an enhancement of cortical gray matter abnormalities when both conditions co-occur.